1. Field of the Invention
This invention relates to a printed wiring board on which electric components are mounted.
2. Description of the Related Art
Generally, various electronic devices, for example, a light such as headlights and a rear light, and a motor such as a starter motor and a motor for an air conditioner, are mounted in a vehicle as a mobile object. A junction block is arranged on a vehicle so as to provide these electronic devices with electrical power. The junction block is included by putting together various electric circuit units of multiple fuses and relays.
Also, a junction block has fuses, relays and bus bars. Thereby, the junction block is called a fuse box, a relay box or an electric connection box. In the present specification, the above mentioned fuse box, the relay box and the junction block are referred to as an electric connection box.
For example, a power distribution unit which internally receives electric component such as relays and fuses is equipped with an electric connection box. Electric power from a battery is inputted into the power distribution unit, and the electric power is output into each electronic devices through electric components received into the power distribution unit. In addition, these electric components are mounted on the printed wiring board. It is required that the power distribution unit is made smaller and lighter.
The printed wiring board has an insulation board, a conductive pattern, a through-hole and a land. The conductive pattern is arranged on the board and formed by a predetermined circuit. A terminal of an electric component is inserted into the through-hole penetrating the board. The land is disposed on a periphery of the through-hole.
A relatively small electric component such as a resistor is temporarily fixed on the printed wiring board by bending a terminal, which is inserted into the through-hole and projects from a surface side of the board, close to the surface of the board. Thereafter, the electric component is soldered to the printed wiring board. Thereby, in a soldering process, even if a molten solder is sprayed near the terminal and the through-hole, the electric component is soldered to a desired position without displacement. However, when the terminal is bent, a tip of the terminal damages a conductive pattern. As a result, there is a possibility that the conductive pattern cannot conduct electricity, and the tip of the terminal causes a short-circuit by connecting the tip with an adjacent conductive area.
The following printed wiring board is designed for solving the above mentioned problems (for example, see the patent document 1). The land of such a printed wiring board is formed into a teardrop shape. The terminal of the printed wiring board is bent along a longitudinal direction, and arranged on the land. Thereby, the terminal does not come in contact with the conductive pattern.
Patent document 1:
Japan published patent application 2005-51133